Mercurial > hg > ucx / file diff

--- a/src/array_list.c	Sun Nov 23 12:19:24 2025 +0100
+++ b/src/array_list.c	Sun Nov 23 13:15:19 2025 +0100
@@ -417,21 +417,23 @@
     // while there are both source and buffered elements left,
     // copy them interleaving
     while (si < elem_count && bi < new_size) {
-        // determine how many source elements can be inserted
+        // determine how many source elements can be inserted.
+        // the first element that shall not be inserted is the smallest element
+        // that is strictly larger than the first buffered element
+        // (located at the index of the infimum plus one).
+        // the infimum is guaranteed to exist:
+        // - if all src elements are larger,
+        //   there is no buffer, and this loop is skipped
+        // - if any src element is smaller or equal, the infimum exists
+        // - when all src elements that are smaller are copied, the second part
+        //   of this loop body will copy the remaining buffer (emptying it)
+        // Therefore, the buffer can never contain an element that is smaller
+        // than any element in the source and the infimum exists.
         size_t copy_len, bytes_copied;
-        copy_len = cx_array_binary_search_sup(
-                src,
-                elem_count - si,
-                elem_size,
-                bptr,
-                cmp_func
+        copy_len = cx_array_binary_search_inf(
+            src, elem_count - si, elem_size, bptr, cmp_func
         );
-        // binary search gives us the smallest index;
-        // we also want to include equal elements here
-        while (si + copy_len < elem_count
-                && cmp_func(bptr, src+copy_len*elem_size) == 0) {
-            copy_len++;
-        }
+        copy_len++;
 
         // copy the source elements
         if (copy_len > 0) {